U.S. patent application number 14/605143 was filed with the patent office on 2016-07-28 for time efficient group data acknowledgement.
The applicant listed for this patent is MOTOROLA SOLUTIONS, INC. Invention is credited to THOMAS B. BOHN.
Application Number | 20160218834 14/605143 |
Document ID | / |
Family ID | 56432874 |
Filed Date | 2016-07-28 |
United States Patent
Application |
20160218834 |
Kind Code |
A1 |
BOHN; THOMAS B. |
July 28, 2016 |
TIME EFFICIENT GROUP DATA ACKNOWLEDGEMENT
Abstract
A method and apparatus for time-efficient confirmed group data
acknowledgement includes a radio subscriber unit (SU) configured to
(i) generate a receive status message comprising a first
synchronization pattern indicating successful receipt of a set of
data blocks when the SU has successfully received the set of data
blocks from a base radio, (ii) generate a receive status message
comprising a second synchronization pattern indicating unsuccessful
receipt of a set of data blocks when the SU has not successfully
received the set of data blocks from the base radio, and (iii)
transmit the generated receive status message from the SU to the
base radio during an uplink transmit time interval assigned by the
base radio.
Inventors: |
BOHN; THOMAS B.; (MC HENRY,
IL) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
MOTOROLA SOLUTIONS, INC |
SCHAUMBURG |
IL |
US |
|
|
Family ID: |
56432874 |
Appl. No.: |
14/605143 |
Filed: |
January 26, 2015 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H04W 72/1289 20130101;
H04W 56/0015 20130101; H04L 1/1635 20130101; H04W 72/0446
20130101 |
International
Class: |
H04L 1/16 20060101
H04L001/16; H04W 72/04 20060101 H04W072/04 |
Claims
1. A method comprising: receiving at a radio subscriber unit (SU),
a set of one or more data blocks from a base radio; receiving at
the SU, an indication of a designated uplink transmit time interval
(TTI) during which the SU is scheduled to transmit a receive status
message to the base radio; determining by the SU, whether the SU
has successfully received each data block in the set of one or more
data blocks; and in response to determining that the SU has
successfully received each of the one or more data blocks, the SU
transmitting a receive status message during the designated uplink
TTI to the base radio, wherein the receive status message comprises
a first synchronization pattern indicating that the SU successfully
received each data block in the set of the one or more data
blocks.
2. The method of claim 1, wherein the receive status message
further comprises a first group data receive status indicator
separate from the first synchronization pattern, wherein the first
group data receive status indicator also indicates that the SU
successfully received each data block in the set of the one or more
data blocks.
3. The method of claim 1, further comprising: in response to
determining that the SU did not successfully receive each data
block in the set of the one or more data blocks, the SU
transmitting a receive status message to the base radio during the
designated uplink TTI, wherein the receive status message comprises
a second synchronization pattern indicating that the SU did not
successfully receive each data block in the set of the one or more
data blocks.
4. The method of claim 3, wherein the receive status message
further comprises a second group data receive status indicator
separate from the second synchronization pattern, wherein the
second group data receive status indicator also indicates that the
SU did not successfully receive each data block in the set of the
one or more data blocks.
5. The method of claim 3, wherein the first synchronization pattern
is either complementary to the second synchronization pattern or
uncorrelated with the second synchronization pattern.
6. The method of claim 1 wherein the SU determining whether the SU
has successfully received each data block in the set of one or more
data blocks comprises one or both of (i) the SU analyzing a block
cyclic redundancy check (CRC) in each data block of the set of one
or more blocks and/or (ii) the SU analyzing a message CRC for the
set of one or more data blocks.
7. The method of claim 1, wherein successful receipt comprises one
or both of (i) the SU receiving each data block without an error or
(ii) the SU successfully correcting all detected errors in each
data block received with one or more errors.
8. The method of claim 1, wherein the assigned uplink TTI is one of
(i) a single uplink timeslot or (ii) one of a plurality of
microslots contained within a single uplink timeslot.
9. The method of claim 8, wherein the receive status message
further comprises a microslot field that indicates a microslot of
an uplink timeslot during which the SU transmitted the receive
status message to the base radio.
10. The method of claim 1, wherein the receive status message
further comprises (i) a system identification field comprising
system identification information and (ii) a parity field
comprising error-correction code.
11. A radio subscriber unit (SU) comprising: one or more wireless
communications interfaces configured to receive (i) a set of one or
more data blocks from a base radio and (ii) an indication of a
designated uplink transmit time interval (TTI) during which the SU
is scheduled to transmit a receive status message to the base
radio; and one or more processors configured to (i) determine
whether the SU has successfully received each of the one or more
data blocks and (ii) in response to determining that the SU has
successfully received each of the one or more data blocks, generate
a receive status message comprising a first synchronization pattern
indicating that the SU successfully received each data block in the
set of the one or more data blocks; wherein the one or more
wireless communications interfaces are further configured to
transmit the generated receive status message to the base radio
during the designated uplink TTI.
12. The radio SU of claim 11, wherein the receive status message
further comprises a first group data receive status indicator
separate from the first synchronization pattern, and wherein the
first group data receive status indicator also indicates that the
SU successfully received each data block in the set of the one or
more data blocks.
13. The radio SU of claim 11, wherein the one or more processors
are further configured to, in response to determining that the SU
did not successfully receive each data block in the set of the one
or more data blocks, generate a receive status message comprising a
second synchronization pattern indicating that the SU did not
successfully receive each data block in the set of the one or more
data blocks.
14. The radio SU of claim 13, wherein the receive status message
further comprises a second group data receive status indicator
separate from the second synchronization pattern, and wherein the
second group data receive status indicator also indicates that the
SU did not successfully receive each data block in the set of the
one or more data blocks.
15. The radio SU of claim 13, wherein the first synchronization
pattern is either complementary to the second synchronization
pattern or uncorrelated with the second synchronization
pattern.
16. The radio SU of claim 11, wherein the one or more processors
are configured to determine whether the SU has successfully
received each of the one or more data blocks by one or both of (i)
analyzing a block cyclic redundancy check (CRC) in each data block
of the one or more blocks, and/or (ii) analyzing a message CRC for
the one or more data blocks.
17. The radio SU of claim 11, wherein the assigned uplink TTI is
one of (i) a single uplink timeslot or (ii) one of a plurality of
microslots contained within a single uplink timeslot.
18. The radio SU of claim 17, wherein the receive status message
further comprises a microslot field that indicates a microslot of
an uplink timeslot during which the SU transmitted the receive
status message to the base radio.
19. The radio SU of claim 11, wherein the receive status message
further comprises (i) a system identification field comprising
system identification information and (ii) a parity field
comprising error-correction code.
20. A tangible, non-transitory computer-readable data storage
comprising instructions that, when executed by one or more
processors of a radio subscriber unit (SU), cause the SU to perform
a method comprising: receiving a set of one or more data blocks
from a base radio; receiving an indication of a designated uplink
transmit time interval (TTI) from the base radio, during which the
SU is scheduled to transmit a receive status message to the base
radio; determining whether the SU has successfully received every
one of the one or more data blocks; in response to determining that
the SU has successfully received every data block in the set of the
one or more data blocks, generating a receive status message
comprising a first synchronization pattern indicating that the SU
successfully received every data block in the set of the one or
more data blocks; in response to determining that the SU has not
successfully received every data block in the set of the one or
more data blocks, generating a receive status message comprising a
second synchronization pattern indicating that the SU has not
successfully received every data block in the set of the one or
more data blocks; and initiating the transmission of the generated
receive status message to the base radio during the designated
uplink TTI.
Description
BACKGROUND OF THE INVENTION
[0001] Some wireless communications systems can be configured to
logically group sets of mobile wireless radio subscriber units
(SUs) into subgroups, sometimes known as talk groups. A talk group
includes multiple SUs that are able to participate in a group or
dispatch voice call, where all of the SUs in the talk group receive
the same voice information, thereby allowing one member of the talk
group (or perhaps a dispatcher at a head end location) to talk to
every other member of the talk group at substantially the same time
over a single shared downlink connection from a base radio.
[0002] Some wireless communication systems also support the
transmission of group data (in addition to group voice) to all SUs
in the talk group. In operation, all of the SUs in the talk group
typically receive group data on a single shared downlink connection
from the base radio. Examples of group data that SUs in a talk
group might receive on the shared downlink connection from the base
radio include text messages, file downloads, SU firmware/software
updates, SU configuration parameter settings, access/encryption
keys, talk group configuration and/or management parameters, and
the like.
[0003] Most wireless communications systems that allow SUs in a
talk group to receive group data messages typically support only
unconfirmed delivery of the group data by the SUs in the talk
group. Unconfirmed delivery is when the base radio sends the group
data to the SUs in the talk group, but the SUs of the talk group do
not inform the base radio as to whether they successfully received
the group data transmission or not. The primary reasons why most
wireless communications systems support only unconfirmed delivery
of group data is because (i) existing methods of sending
confirmation messages from each SU to the base radio use a lot of
radio frequency (RF) resources in the shared wireless network, (ii)
for talk groups with a lot of SUs, existing methods of sending
confirmation messages from each SU to the base radio take a lot of
time especially over lower speed communication channels, and (iii)
it is often unnecessary for individual SUs to send receipt
confirmations to the base radio if higher layer protocols handle
confirmations and retransmission requests (e.g., Transmission
Control Protocol (TCP) between the source application and the
receiver, or perhaps even higher application layer protocols).
[0004] However, in some situations, it is desirable to have the
ability to quickly confirm whether all the SUs in a talk group have
received a particular group data transmission. One such application
is where a large team of operational and/or technical personnel
need to receive the same information (e.g., system alarms,
security/access codes, text messages, system status updates) very
quickly and accurately to coordinate their activities in a
large-scale, mission-critical manufacturing, production,
communications, and/or police/military operation. In such
applications, existing methods of having each SU in the talk group
send a confirmation to the base radio and existing methods of using
Layer 4 (e.g., TCP) or higher (e.g., application layer)
confirmation and retransmission mechanisms may not provide
sufficiently fast delivery confirmations, particularly in talk
groups having a very large number of SUs communicating over lower
speed transmission channels.
[0005] Accordingly, there is a need for an improved, bandwidth
efficient and time efficient, group data acknowledgement to confirm
successful delivery of group data to all SUs in a talk group.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
[0006] The accompanying figures, where like reference numerals
refer to identical or functionally similar elements throughout the
separate views, together with the detailed description below, are
incorporated in and form part of the specification, and serve to
further illustrate embodiments of concepts that include the claimed
invention, and explain various principles and advantages of those
embodiments.
[0007] FIG. 1 is a simplified block diagram of a wireless
communications network configured for operation in accordance with
some embodiments.
[0008] FIG. 2 is a simplified diagram of a transmission flow from a
base radio to a plurality of radio subscriber units in a talk group
in accordance with some embodiments.
[0009] FIG. 3 is a simplified diagram of a receive status message
sent from a radio subscriber unit to a base radio in accordance
with some embodiments.
[0010] FIG. 4 is a simplified block diagram of a base radio in
accordance with some embodiments.
[0011] FIG. 5 is a simplified block diagram of a radio subscriber
unit in accordance with some embodiments.
[0012] FIG. 6 is a flowchart of a method of group data receipt
acknowledgement in accordance with some embodiments.
[0013] Skilled artisans will appreciate that elements in the
figures are illustrated for simplicity and clarity and have not
necessarily been drawn to scale. For example, the dimensions of
some of the elements in the figures may be exaggerated relative to
other elements to help to improve understanding of embodiments of
the present invention.
[0014] The apparatus and method components have been represented
where appropriate by conventional symbols in the drawings, showing
only those specific details that are pertinent to understanding the
embodiments of the present invention so as not to obscure the
disclosure with details that will be readily apparent to those of
ordinary skill in the art having the benefit of the description
herein.
DETAILED DESCRIPTION OF THE INVENTION
[0015] Disclosed herein are systems and methods of bandwidth
efficient and time efficient group data acknowledgement to confirm
successful delivery of group data to all SUs in a talk group. Some
embodiments include an SU configured to: (i) receive a set of one
or more data blocks from a base radio; (ii) determine whether the
SU has successfully received each and every one of the set of one
or more data blocks from the base radio; (iii) receive an
indication of a designated uplink transmit time interval (TTI) from
the base radio during which the SU is scheduled to transmit a
receive status message to the base radio; (iv) in response to
determining that the SU has successfully received every data block
in the set of the one or more data blocks from the base radio,
generate a receive status message comprising a first
synchronization pattern indicating that the SU successfully
received every data block in the set of the one or more data blocks
from the base radio; and (v) transmit the generated receive status
message to the base radio during the designated uplink TTI.
[0016] In another embodiment, a radio SU comprises: one or more
wireless communications interfaces configured to receive (i) a set
of one or more data blocks from a base radio and (ii) an indication
of a designated uplink transmit time interval (TTI) during which
the SU is scheduled to transmit a receive status message to the
base radio, and one or more processors configured to (i) determine
whether the SU has successfully received each of the one or more
data blocks and (ii) in response to determining that the SU has
successfully received each of the one or more data blocks, generate
a receive status message comprising a first synchronization pattern
indicating that the SU successfully received each data block in the
set of the one or more data blocks, wherein the one or more
wireless communications interfaces are further configured to
transmit the generated receive status message to the base radio
during the designated uplink TTI.
[0017] FIG. 1 is a simplified block diagram of an example wireless
communications network 100 configured for operation in accordance
with some embodiments. Wireless communications network 100 includes
a base radio 102 configured to provide wireless communications
service to multiple radio subscriber units (SUs)
104.sub.1-104.sub.m within wireless communications coverage area
106 via a shared wireless communications channel 108.
[0018] The shared wireless communications channel 108 includes
communication resources, e.g., radio frequency (RF) resources, such
as time division multiple access (TDMA) timeslots over which
information is sent between the base radio 102 and the SUs
104.sub.1-104.sub.m in the wireless communication network 100. In
some embodiments, the wireless network 100 may be configured to
operate according to the European Telecommunications Standard
Institute (ETSI) Digital Mobile Radio (DMR) standard and related
protocols. However, in other embodiments, the wireless network may
operate according to any multiple access technology, including but
not limited to other TDMA-based schemes, Frequency Division
Multiple Access (FDMA), Code Division Multiple Access (CDMA), other
multiple access technologies, and/or perhaps combinations of the
above-listed multiple access technologies.
[0019] The SUs 104.sub.1-104.sub.m may be any type of wireless
access terminal, mobile radio, mobile station, wireless
communication device, user equipment, mobile device, or any other
device capable of wireless communication over the shared
communications channel 108 according to the multiple access
protocol(s) of wireless communications network 100. Example SUs
include, but are not limited to, two-way radios, mobile phones,
cellular phones, personal digital assistants, laptops, and
pagers.
[0020] Each of the SUs 104.sub.1-104.sub.m shown in wireless
communications network 100 is a member of the same talk group. A
talk group is a group of SUs configured to communicate group data
with each other and the base radio 102 over the shared
communication channel 108. Group data refers to data that is sent
over the shared communications channel 108 to all SUs within the
talk group. Group data includes, but is not limited to (i) user
data (e.g., text messages, system alarms, and file transfers), (ii)
SU control/management data (e.g., SU firmware, SU configuration
parameters, and security/access keys), and (iii) other SU and/or
talk group management messages and configuration parameters. In
operation, a talk group may include as little as a few (e.g.,
<10) up to many tens or perhaps hundreds of SUs.
[0021] The base radio 102 may be any type of network infrastructure
device capable of sending information to/from multiple SUs
according to the multiple access protocol(s) of the wireless
communications network 100. For example, the base radio 102 may
include one or more base stations, base transceiver stations,
access points, routers, servers, repeaters, or other types of
infrastructure equipment configured for sending and receiving
transmissions in a wireless network such as wireless communications
network 100.
[0022] In some embodiments, the base radio 102 may additionally
include (or at least communicate with) a radio application
server/console (not shown) configured to manage various aspects of
the wireless communications network 100, including but not limited
to operational aspects of the base radio 102 and the SUs
104.sub.1-104.sub.m. In such embodiments, the base radio 102 (alone
or in combination with an integrated or attached application
server/console) monitors the success or failure of the delivery of
group data to the plurality of SUs 104.sub.1-104.sub.m. For
example, the base radio 102 may be configured to confirm delivery
of group data to the SUs 104.sub.1-104.sub.m and/or track the
success or failure of the delivery of the group data to the SUs
104.sub.1-104.sub.m based on acknowledgement (ACK) and
non-acknowledgement (NACK) messages that the SUs in the talk group
transmit to the base radio 102, as described herein.
[0023] FIG. 2 is a simplified diagram of a transmission flow 200
from a base radio to a plurality of SUs in a talk group in
accordance with some embodiments. The example transmission flow 200
includes a data transmission period 202 followed by a hangtime
period 204. In operation, the base radio that transmits the flow
200 may be the same as or similar to any of the base radios
described herein, including base radio 102, shown and described
with reference to FIG. 1. Similarly, the SUs in the talk group that
receive the flow 200 may be the same as or similar to any of the
SUs described herein, including but not limited to SUs
104.sub.1-104.sub.m shown and described with reference to FIG.
1.
[0024] During the data transmission period 202, the base radio
transmits a plurality of data blocks 206-212 to all of the SUs in
the talk group over a shared communications channel. The shared
communications channel may be the same as or similar to the shared
communications channel 108 shown and described with reference to
FIG. 1. In some embodiments, each data block is a 30-millisecond
transmission (or 30-millisecond timeslot) that corresponds to or
includes approximately 288 bits of data at a 9.6 Kbps transmission
rate. In other embodiments, each data block may include more or
fewer bits of data at correspondingly higher or lower transmission
rates. In operation, the base radio may transmit many tens or
hundreds (or perhaps more) of data blocks during the data
transmission period 202.
[0025] In some embodiments, an individual data block, such as data
block 206, includes one or more of (i) a header field 214, (ii) a
group data field 216, and (iii) a block cyclic redundancy check
(CRC) field 218.
[0026] The header field 214 may include one or more of (i) a talk
group identifier to identify the talk group to which the data block
is addressed, (ii) a data block sequence number that indicates the
order in which the block was transmitted, and/or (iii) other
overhead information. In some embodiments, the data block may be
encoded according to an error-correcting code, and in such
embodiments, the header may additionally include data for use by
SUs to detect and potentially correct errors in the transmission of
the data blocks from the base radio to the SUs.
[0027] The group data field 216 may include one or more of (i) user
data (e.g., text messages, system alarms, file transfers) and/or
(ii) SU, talk group, or wireless network control data (e.g.,
signaling to join/leave a talk group, SU configuration information,
talk group configuration information).
[0028] The block CRC field 218 of an individual data block includes
bits corresponding to error-detecting code. In some embodiments, an
individual SU uses the CRC code in the block CRC field 218 of an
individual data block to determine whether the SU has received the
data block without transmission errors. In some embodiments, each
SU in the talk group performs a CRC analysis on each data block
received from the base radio during the data transmission period
202. Because each SU in the talk group performs a CRC analysis on
each data block received, each SU is able to determine, at the end
of the data transmission period 202, whether it received each and
every data block during transmission period 202 without
transmission error(s). In some embodiments, the transmissions from
the base radio during the data transmission period 202 may also
include a message CRC (not shown) that the SUs in the talk group
can additionally or alternatively use to determine whether they
received the each and every data block of the group data
transmitted during the transmission period 202.
[0029] After the data transmission period 202, the base radio
begins the hangtime period 204. During the hangtime period 204, the
base radio transmits a plurality of acknowledgement polls 220-226
to all of the SUs in the talk group. In some embodiments, each
acknowledgement poll is a 30-millisecond transmission (or timeslot)
that corresponds to or includes approximately 288 bits of data at a
9.6 Kbps transmission rate. In other embodiments, each data block
may include more or fewer bits of data at correspondingly higher or
lower transmission rates.
[0030] Each acknowledgement poll includes one or more indications
of one or more uplink transmit time intervals (TTIs) during which
one or more corresponding SUs are scheduled to transmit a receive
status message (FIG. 3) to the base radio to inform the base radio
whether the SU received all of the data blocks (that the base radio
transmitted during data transmission period 202) without error. In
operation, the receive status message that an individual SU sends
to the base radio during its designated TTI is either (i) an ACK
message to inform the base radio that the SU successfully received
all of the data blocks transmitted by the base radio during the
data transmission period 202 or (ii) a NACK message to inform the
base radio that the SU did not successfully receive all of the data
blocks transmitted by the base radio during the data transmission
period 202.
[0031] In the example shown in FIG. 2, acknowledgement poll 220
includes (i) a first indication 230 of a first TTI during which a
first SU (i.e., SU.sub.1) is scheduled to transmit a receive status
message (an ACK or NACK) to the base radio; (ii) a second
indication 232 of a second TTI during which a second SU (SU.sub.2)
is scheduled to transmit a receive status message (an ACK or NACK)
to the base radio; and (iii) a third indication 234 of a third TTI
during which a third SU (SU.sub.3) is scheduled to transmit a
receive status message (an ACK or NACK) to the base radio.
Similarly, acknowledgement poll 226 includes (i) an indication 240
of a TTI during which SU.sub.m-2 is scheduled to transmit a receive
status message to the base radio; (ii) an indication 242 of a TTI
during which SU.sub.m-1 is scheduled to transmit a receive status
message to the base radio; and (iii) an indication 244 of a TTI
during which SU.sub.m is scheduled to transmit a receive status
message to the base radio.
[0032] In some embodiments, each uplink TTI indicated in an
acknowledgement poll message corresponds to one of a plurality of
microslots within a larger uplink timeslot. As described earlier,
downlink transmissions from the base radio to the SUs are arranged
in 30-millisecond timeslots that include up to 288 bits of data at
a 9.6 Kbps data rate. In some embodiments, uplink transmissions
from SUs to the base radio are also arranged in 30-millisecond
timeslots that include up to 288 bits of data at a 9.6 Kbps data
rate. In some embodiments, each acknowledgement poll message may
instruct three separate SUs to transmit their respective receive
status messages during the same 30-millisecond timeslot on the
uplink to the base radio, but during three different microslots
within the 30-millisecond uplink timeslot.
[0033] In such embodiments, each TTI in an acknowledgement poll
message corresponds to one microslot within a larger uplink
timeslot. For example, in acknowledgement poll 220, (i) the first
TTI indicated in field 230 instructs the first SU (SU.sub.1) to
transmit its receive status message to the base radio during the
first microslot of an uplink timeslot, (ii) the second TTI
indicated in field 232 instructs the second SU (SU.sub.2) to
transmit its receive status message to the base radio during the
second microslot of the uplink timeslot, and (iii) the third TTI
indicated in field 234 instructs the third SU (SU.sub.3) to
transmit its receive status message to the base radio during the
third microslot of the uplink timeslot. Similarly, in
acknowledgement poll 226, (i) the TTI indicated in field 240
instructs the SU.sub.m-2 to transmit its receive status message to
the base radio during the first microslot of an uplink timeslot,
(ii) the TTI indicated in field 242 instructs the SU.sub.m-1 to
transmit its receive status message to the base radio during the
second microslot of the uplink timeslot, and (iii) the TTI
indicated in field 244 instructs the SU.sub.m to transmit its
receive status message to the base radio during the third microslot
of an uplink timeslot. It will be readily appreciated that the
uplink timeslot (and thus the TTIs indicated in fields 230, 232,
and 234) for SU.sub.1, SU.sub.2, and SU.sub.3 of acknowledgment
poll 220 is a different uplink timeslot than the uplink timeslot
(and thus the TTIs indicated in fields 240, 242, and 244) for
SU.sub.m-2, SU.sub.m-1, and SU.sub.m indicated in acknowledgement
poll 226.
[0034] Each acknowledgment poll may also include a header field and
a block CRC field. For example, acknowledgement poll 220 also
includes a header field 228 that may include a talk group
identifier to identify the talk group to which the acknowledgement
poll is addressed and/or perhaps other overhead information.
Similarly, acknowledgement poll 226 also includes a header field
238 that may include the talk group identifier to identify the talk
group to which the acknowledgement poll is addressed and/or perhaps
other overhead information.
[0035] The block CRC field of each acknowledgement poll includes
bits corresponding to error-detecting code so that each SU in the
talk group that receives an acknowledgement poll can determine
whether it received that particular acknowledgement poll without
error. For example, acknowledgement poll 220 includes block CRC
field 236 that includes error-detecting code that SUs in the talk
group can use to determine whether they received acknowledgement
poll 220 without error, and acknowledgment poll 226 includes block
CRC field 248 that includes error-detecting code that SUs in the
talk group can use to determine whether they received
acknowledgment poll 226 without error.
[0036] In operation, the base radio sends enough acknowledgement
polls during the hangtime period 204 so that each SU in the talk
group receives its own indication of a corresponding TTI during
which that SU is scheduled to send its own receive status message
to the base radio. In the example embodiment shown in FIG. 2, each
acknowledgement poll includes three such indications. Thus, for a
talk group that includes 90 SUs for example, the base radio only
needs to send 30 acknowledgement poll messages to poll all 90 SUs
because each acknowledgement poll message in effect polls three
separate SUs. As a result, the acknowledgement polling method
described herein is substantially faster (up to 3-times faster)
than polling methods where the base radio polls each SU in a talk
group with a separate, 30-millisecond acknowledgement poll
message.
[0037] FIG. 3 is a simplified diagram of a data transmission 300
comprising an example receive status message 302 sent from an
individual SU to a base radio in accordance with some embodiments.
In operation, each SU in the talk group sends the base radio a
separate receive status message in response to receiving an
acknowledgement poll message from the base radio. The receive
status message 302 that an individual SU transmits to the base
radio may be either (i) an ACK message to indicate to the base
radio that the SU successfully received each and every data block
transmitted by the base radio during the data transmission period
preceding the hangtime period during which the SU received the
acknowledgement poll message; or (ii) a NACK message to indicate to
the base radio that the SU did not successfully receive each and
every data block transmitted by the base radio during the data
transmission period preceding the hangtime period during which the
SU received the acknowledgement poll message.
[0038] As described above, in some embodiments, an individual SU
determines whether it successfully received each and every data
block of a data transmission period by performing a CRC analysis on
each received data block based at least in part on the
error-detection data contained in the block CRC field of each
received data block (FIG. 2). In other embodiments, an individual
SU may perform a CRC analysis on multiple data blocks (or perhaps
all data blocks) transmitted during a data transmission period
based at least in part on error-detection contained in a message
CRC. Regardless of whether the SU performs block-based or
message-based error detection, if the SU determines that it
received each and every data block during the preceding data
transmission period without error, then the receive status message
302 that the SU sends to the base radio will be an ACK message.
Conversely, if the SU determines that it received at least one of
the data blocks during the preceding data transmission period with
a transmission error(s), then the receive status message 302 that
the SU sends to the base radio will be a NACK message.
[0039] In some embodiments, the base radio may encode data blocks
with an error-correcting code prior to transmitting the data blocks
to the SUs in the talk group, thereby enabling SUs to attempt to
correct some transmission errors prior to conducting the
above-described CRC analyses. In such embodiments, the base radio
calculates a block CRC for the group data, inserts the calculated
block CRC into the block CRC field 218, applies forward error
correction (FEC) to the group data and block CRC, and transmits the
data block to the SUs in the talk group. When an SU receives the
data block, the SU uses FEC to attempt to correct transmission
errors, and then uses the block CRC to detect block errors.
[0040] The example receive status message 302 shown in FIG. 3
includes a short response 304 that is broken into a first half
304(a) and a second half 304(b) separated by a synchronization
field 306. In operation, the synchronization field 306 includes a
synchronization pattern that the SU uses both for (i) transmission
synchronization and (ii) to indicate ACK or NACK to the base
radio.
[0041] In particular, the SU transmits the synchronization pattern
in the synchronization field 306 to enable a receiver at the base
radio to perform frame and/or symbol alignment on incoming
transmissions so that the data within the 30-millisecond uplink
timeslot can be extracted and decoded. The synchronization pattern
is a distinctive bit sequence (sometimes referred to as a syncword)
known by the receiver. As described in more detail below, in some
embodiments, a 30-millisecond uplink timeslot may be sub-divided
into 3 microslots to enable three separate SUs to each transmit a
separate receive status message in a separate microslot within the
single 30-millisecond uplink timeslot. In operation, the receiver
at the base radio uses the known synchronization pattern in each
receive status message in each microslot to symbol align each
incoming receive status message. In some embodiments, the
synchronization pattern may be a preamble at the beginning of a
transmission or a midamble in the middle of a transmission.
[0042] As mentioned above, the SU also uses the synchronization
pattern in the synchronization field 306 to indicate ACK or NACK to
the base radio. In particular, the SU transmits a first
synchronization pattern in the synchronization field 306 to
indicate an ACK, or the SU transmits a second (different)
synchronization pattern in the synchronization field 306 to
indicate a NACK. In some embodiments, the first and second
synchronization patterns may be "sync pairs," or complements of
each other, meaning that the bits or symbols of the first
synchronization pattern are the opposite of the bits or symbols of
the second synchronization pattern, thereby resulting in a low
degree of falsing. Using either bit-wise or symbol-wise
complementary first and second synchronization patterns may also
enable the receiver at the base radio to use a single matching
algorithm to detect both the first and second synchronization
patterns. Alternatively, the first and second synchronization
patterns may be sufficiently uncorrelated (but perhaps not
complementary) such that the receiver at the base radio can
reliably differentiate between the first and second synchronization
patterns.
[0043] In operation, if the SU has successfully received each and
every data block in the preceding data transmission period, then
the SU will insert the first synchronization pattern into the
synchronization field 306 of the receive status message 302 that it
sends to the base radio. The first synchronization pattern
indicates an ACK, i.e., a confirmation to the base radio that the
SU successfully received each and every data block in the preceding
data transmission period. But if the SU did not successfully
receive each and every data block in the preceding data
transmission period, the SU will insert the second synchronization
pattern into the synchronization field 306 of the receive status
message 302 that it sends to the base radio. This second
synchronization pattern indicates a NACK, i.e., an indication to
the base radio that the SU did not successfully receive each and
every data block in the preceding data transmission period.
[0044] As mentioned earlier, an SU may determine whether it has
successfully received each and every data block in a preceding data
transmission period by multiple methods. For example, in some
embodiments, the SU may analyze the block CRC in each received data
message to determine, on a block-by-block basis, whether it
successfully received each data block during the data transmission
period. In other embodiments, the SU may additionally or
alternatively analyze a message CRC corresponding to all of the
data blocks sent during the preceding data transmission period to
determine whether it received each and every data block transmitted
by the base radio during the preceding data transmission
period.
[0045] Because the SUs must transmit a synchronization pattern to
enable the receiver at the base radio to decode the receive status
message, and because the first and second synchronization patterns
are known and can be differentiated by the receiver at the base
radio, the SUs in the talk group can use the first and second
synchronization patterns to indicate ACK and NACK without having to
transmit any additional bits beyond the bits in the synchronization
pattern that they already must send anyway. Thus, by using the
first and second synchronization patterns for both transmission
synchronization and to indicate ACK and NACK, for example at a
Layer 2 of the Open Systems Interconnection (OSI) model, the
disclosed embodiments reduce the bandwidth required for SUs to
indicate ACK and NACK to the base radio as compared to alternative
methods where SUs might use bits that are are separate and distinct
from the bits in the synchronization pattern to indicate ACK or
NACK to the base radio.
[0046] The receive status message 302 also includes a short
response 304. In some embodiments, the short response 304 may
include one or more of (i) a system identification field, (ii) a
confirmed group data response field, (iii) a microslot field,
and/or (iv) a FEC parity field. In the example receive status
message 302 shown in FIG. 3, the short response 304 includes a
system identifier field 308, a confirmed group data response field
310, a microslot field 312, and a FEC parity field 314.
[0047] The system identifier field 308 contains a system identifier
(system ID) that may identify the particular network that the
transmitting SU is configured to operate on and/or the transmitting
SU's talk group.
[0048] Embodiments that include a group data response field may
utilize the group data response field to transmit an additional ACK
or NACK indication to the base radio. In embodiments like the
example shown in FIG. 3, the SU can use the group data response
field 310, which is separate from the synchronization field 306 in
the receive status message 302, to additionally indicate whether
the SU successfully received each and every data block transmitted
during the preceding data transmission period. As mentioned
earlier, the SU may determine whether it received each and every
data block transmitted during the preceding data transmission
period by (i) analyzing the block CRC in each data block received
during the preceding transmission period and/or (ii) analyzing a
message CRC for all of the data blocks transmitted by the base
radio during the preceding data transmission period. If the SU
determines that it successfully received each and every data block,
then the SU inserts an ACK indication into the confirmed group data
response field 310. But if the SU determines that it did not
successfully receive each and every data block in the preceding
data transmission period, then the SU inserts a NACK indication
into the confirmed group data response field 310.
[0049] By indicating ACK or NACK in two parts of the receive status
message 302 (i.e., in the synchronization field 306 and the
confirmed group data response field 310), an SU can enable the base
radio to perform a form of error-detection and more reliably
determine ACK or NACK to prevent or at least help reduce instances
of falsing (i.e., a scenario where a weak signal or data
transmission error(s) causes the base radio to decode a NACK as an
ACK or vice versa) than if the SU indicated ACK or NACK in only one
field of the receive status message 302. This capability can be
useful in embodiments such as the example shown in FIG. 3, where
the receive status message 302 does not include a CRC field for
error detection. Moreover, the system can achieve this improved
reliability with as little as a single bit, i.e., the 1-bit
confirmed group data response field 310 (although some embodiments
may use a group data response field larger than 1 bit to convey
more than ACK and NACK). In particular, the base radio can examine
both (i) the synchronization pattern within the synchronization
field 306 and (ii) the indication in the confirmed group data
response field 310. If the synchronization pattern indicates an ACK
and the confirmed group data response also indicates an ACK, then
the base radio can be fairly confident that it received an ACK from
an SU. Likewise, if the synchronization pattern indicates a NACK
and the confirmed group data response also indicates a NACK, the
base radio can be fairly confident that it received a NACK from an
SU.
[0050] Further, some embodiments may additionally use the system ID
contained in the system identifier field 308 to aid in
error-detection. For example, in ETSI DMR embodiments, each receive
status message that each SU in a talk group transmits to a base
radio includes the same system ID in the system identifier field
308. Because the receiver at the base radio knows what the system
ID for each receive status message should be, the receiver can use
a combination of the system ID in the system identifier field 308,
the synchronization pattern in the synchronization field 306, and
the ACK/NACK indication in the group data response field 310 to
improve its level of confidence in the accuracy of a receive status
message received from an SU.
[0051] In some embodiments, the base radio may first check to
determine if the system ID in the system identifier field 308
matches the expected system ID. If the system ID in the system
identifier field 308 does not match the expected system ID, the
base radio may discard the message as either erroneous or perhaps
intended for another receiver. But if the system ID in the system
identifier field 308 matches the expected system ID, then the base
radio may then determine (i) whether the group data response field
310 indicates an ACK or a NACK, (ii) whether the synchronization
pattern in the synchronization field 306 indicates an ACK or a
NACK, and (iii) whether the receive status (ACK or NACK) indicated
by the data in the group data response field 310 matches the
receive status (ACK or NACK) indicated by the synchronization
pattern in the synchronization field 306. If the receive status
indicated in the group data response field 310 matches the receive
status indicated by the synchronization pattern, then the base
radio may conclude that it successfully received the receive status
message. But if the receive status indicated in the group data
response field 310 does not match the receive status indicated by
the synchronization pattern, then the base radio may discard the
receive status message as erroneous. In this manner, the base radio
can additionally use the system ID in the system identifier field
308 to prevent or at least help reduce instances of falsing.
[0052] In some embodiments, the receive status message may also
include a FEC parity field 314 that includes error-correcting code
that the base radio can use to detect and perhaps correct errors in
a particular receive status message that is received from an
individual SU.
[0053] Some embodiments may also include a microslot field 312 that
indicates one of a plurality of microslots during which the SU
transmitted the receive status message 302. As described with
reference to FIG. 2, the base radio transmits data blocks and
acknowledgement poll messages in 30-millisecond timeslots that
include up to 288 bits of data at a 9.6 Kbps data rate. In some
embodiments, transmissions from SUs to the base radio are also
arranged in 30-millisecond timeslots that may include up to 288
bits of data at a 9.6 Kbps data rate.
[0054] In such embodiments, three separate 68-bit long (7.083
milliseconds at a 9.6 Kpbs data rate) receive status messages like
receive status message 302 can be transmitted by three separate SUs
during one 30-millisecond timeslot. And in such embodiments, the
microslot field 312 may indicate which of the three microslots
within the 30-millisecond timeslot that the SU transmitted the
receive status message. Indicating which of the three microslots
within a particular uplink timeslot that the SU transmitted the
receive status message may help the base radio determine which SU
transmitted the receive status message because, in operation, each
SU will transmit its receive status message in one of three
microslots as indicated by the earlier acknowledgement poll message
that the base radio sent to the SU (see FIG. 2).
[0055] Because three SUs can send a reliable receive status message
during a single 30-millisecond uplink timeslot, all of the SUs in a
large talk group with 90 SUs for example can transmit their receive
status messages during thirty total 30-millisecond uplink
timeslots. As a result, the receive status message format described
herein enables all of the SUs in a talk group to separately confirm
receipt of group data substantially faster (up to 3-times faster)
than methods where each SU in the talk group sends a receive status
message in a separate 30-millisecond uplink timeslot.
[0056] Additionally, in some embodiments, an SU may use different
combinations of synchronization patterns (or perhaps "sync pairs"
or combinations of "sync pairs") to indicate ACK or NACK depending
on which microslot the SU is scheduled to transmit its receive
status message to the base radio. For example, if a particular SU
is scheduled to transmit its receive status message during the
first of three microslots, then the SU may use the first
synchronization pattern to indicate an ACK and the second
synchronization pattern to indicate a NACK. But if the SU is
scheduled to transmit its receive status message during the second
of the three microslots, then the SU may instead use the second
synchronization pattern to indicate an ACK and the first
synchronization pattern to indicate a NACK.
[0057] Alternatively, if four synchronization patterns are
available for use in indicating ACK or NACK, an SU may (i) use
synchronization pattern 1 for ACK and synchronization pattern 2 for
NACK if transmitting its receive status message during the first
microslot; (ii) use synchronization pattern 3 for ACK and
synchronization pattern 4 for NACK if transmitting its receive
status message during the second microslot; and (iii) use
synchronization pattern 2 for ACK and synchronization pattern 1 for
NACK if transmitting its receive status message during the third
microslot. Similarly, if three sync pairs (i.e., 6 total
synchronization patterns) are available for use in indicating ACK
or NACK, an SU may (i) use the first synchronization pattern of
sync pair 1 for ACK and the second synchronization pattern of sync
pair 1 for NACK if transmitting its receive status message during
the first microslot; (ii) use the first synchronization pattern of
sync pair 2 for ACK and the second synchronization pattern of sync
pair 2 for NACK if transmitting its receive status message during
the second microslot; and (iii) use the first synchronization
pattern of sync pair 3 for ACK and the second synchronization
pattern of sync pair 3 for NACK if transmitting its receive status
message during the third microslot. Other combinations of
synchronization patterns, sync pairs, and combinations of
synchronization patterns and/or sync pairs for ACK and NACK could
be used as well. In this manner, the base radio is able to use the
microslot identified in field 312 of the receive status message 302
along with the confirmed group data response in field 310 and the
synchronization pattern in field 306 to help determine whether an
individual receive status message was received with or without one
or more errors.
[0058] If the base radio receives a NACK indication from any of the
SUs in the talk group, the base radio may then re-transmit some or
all of the data blocks to some or perhaps all of the SUs in the
talk group.
[0059] FIG. 4 is a simplified block diagram of a base radio 400 in
accordance with some embodiments. The base radio 400 is configured
to operate in a wireless network such as wireless network 100 shown
and described with reference to FIG. 1. In operation, the base
radio 400 may be the same as or similar to base radio 102 shown or
described with reference to FIG. 1.
[0060] The example base radio 400 includes one or more wireless
communications interfaces 402, one or more wired communications
interfaces 410, one or more processors 412, and data storage 414,
all of which may be coupled together by a system bus 418 or similar
mechanism. In addition, the base radio 400 may also include
external storage, such as magnetic or optical disk storage (not
shown). Variations from this arrangement are possible as well,
including addition and/or omission of components, combination of
components, and distribution of components in any of a variety of
ways.
[0061] The base radio 400 components may be arranged to support
wireless communications in a wireless network that is compliant
with one or more of the variety of wireless air-interface protocols
noted herein, in addition to other protocols now known or later
developed. In particular, the components of the example base radio
400 are configured to implement some aspects of time-efficient
group data acknowledgement in accordance with the example
embodiments described herein. For example, base radio 400 may be
configured to generate and send downlink data transmissions to a
plurality of SUs on a shared communication channel, including but
not limited to data transmissions that are the same as or similar
to data flow 200 shown and described with reference to FIG. 2 and
similar data transmissions. Additionally, the base radio 400 may
also be configured to receive and process uplink data transmissions
from SUs to the base radio on a shared communications channel,
including but not limited to data transmissions that are the same
as or similar to the receive status messages shown and described
with reference to FIG. 3 and similar data transmissions.
[0062] The one or more wireless communications interfaces 402
include one or more antennas 404, transmitter circuitry 406,
receiver circuitry 408, and other associated components that enable
the base radio 400 to engage in air interface communication with
one or more SUs, such as SUs 104.sub.1-104.sub.m shown in FIG. 1,
according to any of the air interface protocols disclosed and/or
described herein. In some instances, the transmitter circuitry 406
and receiver circuitry 408 (alone or in combination with the
antenna(s) 404) may be collectively referred to as transceiver
circuitry.
[0063] The one or more wired communications interfaces 410 include
physical network interfaces (e.g., optical, electrical) that enable
the base radio 400 to send and receive data transmissions directly
or indirectly to/from other base radios and additionally or
alternatively to/from one or more local area networks (LAN), wide
area networks (WAN), or other networks, such as the Public Switched
Telephone Network (PSTN), or the Internet. The one or more wired
communications interfaces 418 may take the form of Ethernet network
interfaces, optical network interfaces, or other physical
interfaces to one or more networks that directly or indirectly
connect the base radio 400 to other base radios as well as to LANs,
WANs, or other networks such as the PSTN or the Internet. The one
or more wired communications interfaces 410 may also enable the
base radio 400 to be controlled by one or more wireless network
controllers and/or other network control and management
systems.
[0064] The one or more processors 412 include one or more
general-purpose processors (e.g., microprocessors) and/or one or
more special-purpose processors (e.g., digital signal processors
(DSPs) or application specific integrated circuits (ASICs)).
[0065] The non-transitory data storage 414 includes one or more
volatile and/or non-volatile storage components, such as magnetic
or optical memory or disk storage. Non-transitory data storage 414
can be integrated in whole or in part with the one or more
processors 412, as cache memory or registers for example. In some
embodiments, one or more of the processors 412 and non-transitory
data storage 414 may be integrated in whole or in part with one or
more of the wireless communications interfaces 402 and/or wired
communications interfaces 410.
[0066] In operation, the non-transitory data storage 412 is
configured to hold program instructions 416. The program
instructions 416 include machine language instructions that define
routines and software program code executable by the one or more
processors 412 (alone or in combination with the wireless
communications interface(s) 402 and/or wired communications
interface(s) 410) to implement and/or execute various features and
functions described in the embodiments disclosed herein. For
example, the one or more processors 412 of the base radio 400 may
execute the program instructions 416 in data storage 414 to cause
the base radio 400 to generate, send, receive, and/or process the
data transmissions associated with time-efficient group data
acknowledgement processes and procedures described herein,
including but not limited to those steps, receptions, and/or
transmissions set forth in FIGS. 2, 3, and/or 6.
[0067] FIG. 5 is a simplified block diagram of a radio subscriber
unit (SU) 500 in accordance with some embodiments. The SU 500 is
configured to operate in a wireless communications network such as
network 100 shown and described with reference to FIG. 1.
Similarly, the SU 500 may be the same as or similar to SUs
104.sub.1-104.sub.m shown and described with reference to FIG.
1.
[0068] The example SU 500 includes one or more wireless
communications interfaces 502, one or more user interfaces 516, one
or more processors 510, data storage 512, all of which may be
coupled together by a system bus 518 or similar mechanism.
Variations from this arrangement are possible as well, including
addition and/or omission of components, combination of components,
and distribution of components in any of a variety of ways.
[0069] The SU 500 components may be arranged to support wireless
communications in a wireless communication network that is
compliant with one or more of the variety of wireless air-interface
protocols noted herein, in addition to other protocols now known or
later developed. In particular, the components of the example SU
500 are configured to implement some aspects of time-efficient
group data acknowledgement in accordance with the example
embodiments described herein. For example, SU 500 is configured to
receive and process downlink data transmissions from a base radio
on a shared communication channel, including but not limited to
data transmissions that are the same as or similar to data flow 200
shown and described with reference to FIG. 2 and similar data
transmissions. Additionally, the SU 500 may be configured to
generate and send uplink data transmissions to the base radio on a
shared communications channel, including but not limited to data
transmissions that are the same as or similar to the receive status
messages shown and described with reference to FIG. 3 and similar
data transmissions
[0070] The one or more wireless communications interfaces 502
include one or more antennas 504, transmitter circuitry 506,
receiver circuitry 508, and other associated components that enable
the SU 500 to engage in air interface communication with a base
radio, such as base radio 102 shown in FIG. 1 or the base radio 400
shown in FIG. 4, according to any of the air interface protocols
disclosed and/or described herein. In some instances, the
transmitter circuitry 506 and receiver circuitry 508 (alone or in
combination with the antenna(s) 504) may be collectively referred
to as transceiver circuitry.
[0071] The one or more processors 510 include one or more general
purpose processors (e.g., microprocessors) and/or special purpose
processors (e.g., DSPs, ASICs). In some embodiments, the one or
more processors 510 may be integrated in whole or in part with the
one or more wireless communications interfaces 502.
[0072] The non-transitory, computer-readable data storage 512
comprises one or more volatile and/or non-volatile storage
components. The storage components may include one or more
magnetic, optical, and/or flash memory components for example. In
some embodiments, the non-transitory data storage 512 may be
integrated in whole or in part with the one or more processors 510
and/or the wireless communication interface(s) 502. Additionally or
alternatively, the non-transitory data storage 512 may be provided
separately as a non-transitory machine or computer readable
medium.
[0073] The non-transitory data storage 512 may hold (e.g., contain,
store, or otherwise be encoded with) program instructions 514
(e.g., machine language instructions or other program logic, markup
or the like) executable by the one or more processors 510 to
execute the various functions described herein, including but not
limited to those steps, receptions, and/or transmissions set forth
in FIGS. 2, 3, and/or 6.
[0074] The user interface(s) 516 may include a screen or
touchscreen (e.g., a Liquid Crystal Display (LCD) or similar type
of screen or touchscreen) on which a user may (i) view data (e.g.,
group data like text messages, system alarms, or the like) and/or
(ii) input data SU for (ii-a) controlling and/or configuring the SU
and/or (ii-b) transmitting over the wireless network. The user
interface(s) 516 may also include a set of buttons arranged in a
keypad or similar layout via which a user may input data to the SU
for (i) controlling and/or configuring the SU and/or (ii)
transmitting over the wireless network.
[0075] FIG. 6 is a flowchart of a method 600 of group data receipt
acknowledgement in accordance with some embodiments.
[0076] Method 600 begins at step 602 where an SU receives a set of
one or more data blocks from a base radio. The SU and the base
radio may be the same as or similar to any of the SUs or base
radios shown or described herein. In operation, the SU is one of a
plurality of SUs in a talk group, and the set of one or more data
blocks is transmitted by the base radio to the plurality of SUs in
the talk group during a data transmission period that is similar to
or the same as data transmission period 202 shown and described
with reference to FIG. 2.
[0077] In some embodiments, step 602 also includes the SU
determining, for each data block that it receives (and perhaps on a
block-by-block basis as each data block is received), whether the
SU successfully received that particular data block. For example,
the SU may perform error detection based on an analysis of CRC data
contained within a block CRC field of each received data block as
described herein with reference to FIGS. 2 and 3. But in some
embodiments, the SU may additionally or alternatively perform error
detection based on an analysis of CRC data contained within a
message CRC applicable to multiple data blocks (or perhaps all the
data blocks) transmitted during a single data transmission period.
Successful receipt includes either or both of (i) for systems that
employ forward error correction, detecting and correcting errors in
a data block that was received with one or more errors and/or (ii)
receiving the data block without an error. In operation,
determining successful receipt of an individual data block may
include a combination of error-correction methods alone or in
combination with error-detection methods as shown and described
herein with reference to FIGS. 2 and 3.
[0078] At step 604, the SU receives an indication of an assigned
uplink transmit time interval (TTI) during which to transmit a
receive status message to the base radio. In some embodiments, the
indication of the assigned TTI is contained within one of a
plurality of acknowledgement polling messages that the base radio
sends to the plurality of SUs in the talk group during a hangtime
period following a data transmission period, such as the hangtime
period 204 following the data transmission period 202 shown and
described with reference to FIG. 2. Similarly, in some embodiments,
the acknowledgement polling messages directed to individual SUs are
the same as or similar to the acknowledgement polling messages
shown and described with reference to FIG. 2. Likewise, the
assigned uplink TTI may be a single uplink timeslot or one of a
plurality of microslots contained within a single uplink timeslot
as shown and described herein with reference to FIGS. 2 and 3.
[0079] At step 606, the SU determines whether it successfully
received each and every data block in the set of one or more data
blocks received at step 602. In embodiments where step 602 includes
the SU detecting errors on a block-by-block basis as each data
block is received, step 606 may include the SU referring back to
the outcome of the error detection analysis conducted for each of
the data blocks in the set of one or more data blocks received at
step 602. In other embodiments, the SU may wait to receive some or
all of the data blocks before performing error-detection on the
received data blocks and making any subsequent determination of
whether each and every data block was successfully received. Some
embodiments may additionally or alternatively include the SU
performing an error-detection analysis on a set of multiple (or
perhaps all) data blocks received during a transmission period
based on a message CRC as described herein. As mentioned
previously, successful receipt may include (i) for systems
configured to employ forward error correction, detecting and
correcting errors in a data block that was received with one or
more errors and/or (ii) receiving the data block without an
error.
[0080] At step 608, if the SU has determined that each and every
data block in the set of one or more data blocks received from the
base radio in step 602 was successfully received, then method 600
advances to step 610, where the SU (i) generates a receive status
message comprising a first synchronization pattern indicating that
each data block in the set of one or more data blocks received from
the base radio in step 602 was received successfully and (ii)
transmits the generated receive status message to the base radio
during the assigned uplink TTI received in step 604.
[0081] But if at step 608, the SU determines that each and every
data block in the set of one or more data blocks received from the
base radio in step 602 was not successfully received, then method
600 advances to step 612, where the SU (i) generates a receive
status message comprising a second synchronization pattern
indicating that each data block in the set of one or more data
blocks received from the base radio in step 602 was not received
successfully and (ii) transmits the generated receive status
message to the base radio during the assigned uplink TTI received
in step 604. In operation, the assigned TTI during which the SU
transmits the generated receive status message may be a single
uplink timeslot or one of a plurality of microslots contained
within a single uplink timeslot as shown and described herein with
reference to FIGS. 2 and 3.
[0082] In operation, the receive status message generated and sent
at steps 610 or 612 may be the same as or similar to the receive
status messages shown and described with reference to FIG. 3. For
example, in some embodiments, the receive status messages generated
and sent at steps 610 or 612 may additionally include one or more
of a system identifier, confirmed group data response indication, a
microslot indication, and/or FEC parity data as shown and described
with reference to FIG. 3.
[0083] In the foregoing specification, specific embodiments have
been described. However, one of ordinary skill in the art
appreciates that various modifications and changes can be made
without departing from the scope of the invention as set forth in
the claims below. Accordingly, the specification and figures are to
be regarded in an illustrative rather than a restrictive sense, and
all such modifications are intended to be included within the scope
of present teachings.
[0084] The benefits, advantages, solutions to problems, and any
element(s) that may cause any benefit, advantage, or solution to
occur or become more pronounced are not to be construed as a
critical, required, or essential features or elements of any or all
the claims. The invention is defined solely by the appended claims
including any amendments made during the pendency of this
application and all equivalents of those claims as issued.
[0085] Moreover in this document, relational terms such as first
and second, top and bottom, and the like may be used solely to
distinguish one entity or action from another entity or action
without necessarily requiring or implying any actual such
relationship or order between such entities or actions. The terms
"comprises," "comprising," "has", "having," "includes",
"including," "contains", "containing" or any other variation
thereof, are intended to cover a non-exclusive inclusion, such that
a process, method, article, or apparatus that comprises, has,
includes, contains a list of elements does not include only those
elements but may include other elements not expressly listed or
inherent to such process, method, article, or apparatus. An element
proceeded by "comprises . . . a", "has . . . a", "includes . . .
a", "contains . . . a" does not, without more constraints, preclude
the existence of additional identical elements in the process,
method, article, or apparatus that comprises, has, includes,
contains the element. The terms "a" and "an" are defined as one or
more unless explicitly stated otherwise herein. The terms
"substantially", "essentially", "approximately", "about" or any
other version thereof, are defined as being close to as understood
by one of ordinary skill in the art, and in one non-limiting
embodiment the term is defined to be within 10%, in another
embodiment within 5%, in another embodiment within 1% and in
another embodiment within 0.5%. The term "coupled" as used herein
is defined as connected, although not necessarily directly and not
necessarily mechanically. A device or structure that is
"configured" in a certain way is configured in at least that way,
but may also be configured in ways that are not listed.
[0086] It will be appreciated that some embodiments may be
comprised of one or more generic or specialized processors (or
"processing devices") such as microprocessors, digital signal
processors, customized processors and field programmable gate
arrays (FPGAs) and unique stored program instructions (including
both software and firmware) that control the one or more processors
to implement, in conjunction with certain non-processor circuits,
some, most, or all of the functions of the method and/or apparatus
described herein. Alternatively, some or all functions could be
implemented by a state machine that has no stored program
instructions, or in one or more application specific integrated
circuits (ASICs), in which each function or some combinations of
certain of the functions are implemented as custom logic. Of
course, a combination of the two approaches could be used.
[0087] Moreover, an embodiment can be implemented as a
computer-readable storage medium having computer readable code
stored thereon for programming a computer (e.g., comprising a
processor) to perform a method as described and claimed herein.
Examples of such computer-readable storage mediums include, but are
not limited to, a hard disk, a CD-ROM, an optical storage device, a
magnetic storage device, a ROM (Read Only Memory), a PROM
(Programmable Read Only Memory), an EPROM (Erasable Programmable
Read Only Memory), an EEPROM (Electrically Erasable Programmable
Read Only Memory) and a Flash memory. Further, it is expected that
one of ordinary skill, notwithstanding possibly significant effort
and many design choices motivated by, for example, available time,
current technology, and economic considerations, when guided by the
concepts and principles disclosed herein will be readily capable of
generating such software instructions and programs and ICs with
minimal experimentation.
[0088] The Abstract of the Disclosure is provided to allow the
reader to quickly ascertain the nature of the technical disclosure.
It is submitted with the understanding that it will not be used to
interpret or limit the scope or meaning of the claims. In addition,
in the foregoing Detailed Description, it can be seen that various
features are grouped together in various embodiments for the
purpose of streamlining the disclosure. This method of disclosure
is not to be interpreted as reflecting an intention that the
claimed embodiments require more features than are expressly
recited in each claim. Rather, as the following claims reflect,
inventive subject matter lies in less than all features of a single
disclosed embodiment. Thus the following claims are hereby
incorporated into the Detailed Description, with each claim
standing on its own as a separately claimed subject matter.
* * * * *